Though they’ve been around for decades, the finishes have gone upscale, just as they have in homes. The most lavish versions may even have higher-end features than your own master bath: Think granite-style countertops, six-panel wood-grain doors, an electric fireplace for ambiance.

Naturally, those Houzz-worthy touches — not to mention creature comforts like heating, air conditioning and ventilation — come at a much higher price than the plastic, chemical-based port-a-potties most people are familiar with. Fancy restroom trailers (and they are almost always trailers) could cost up to $2500 to rent for a weekend.

But they’re not just for the polo matches and charity outings of the rich and famous. United Rentals is one company that places these restroom trailers everywhere from music festivals to gas refinery plants to backyard events.

“We will [rent restrooms for] a graduation party in someone’s backyard. We might do a wedding on a beach,” said Jerry Vecchiarelli, regional product development manager for United Rentals.

As the popularity of outdoors weddings rises, so does the demand for luxury restroom trailers, he noted. “If you put a big tent out in a field or at a farm or barn, you’re going to have a bar, food, a band — and all these guests are going to need to go to the bathroom sooner or later.”

Customers who don’t have a lot of cash to spare can get, for a couple hundred bucks, a “deluxe portable restroom” with a flush toilet and a sink with a foot pump so people can wash their hands with running water.

Both luxury restroom trailers and, occasionally, deluxe portable restrooms, are used for construction projects, too — though not necessarily for the construction workers.

“Let’s say there’s an office building where suit-and-tie executives work and they have to remodel the bathrooms. They’re going to rent a higher-end restroom trailer for employees,” Vecchiarelli said. “But for that same building, for the construction workers they’ll probably put port a-potties outside.”

The same goes for bathroom remodeling projects at Wegmans grocery stores and other retailers where United Rentals has placed luxury portable restrooms for customers.

Once in a while, the trailers are rented for lucky workers. For example, in the oil industry, where workers may be in very remote areas, high-end restroom trailers and shower trailers can help boost morale, Vecchiarelli said.

“I think as time goes on, contractors are becoming more exposed to it not just from us but from other providers as well,” Vacchiarelli said. “The biggest challenge we’ve found is educating people that this product even exists.”